The present invention is directed, in general, to optical networking and, more specifically, to an optical backplane for use with a communications equipment chassis, an optical communications system including the same, and a method of operation therefor.
In communications, networking and information technology industries, the reduction of network performance problems, outages, and service delays (collectively xe2x80x9cdowntimexe2x80x9d) is of major concern. Also of concern is the reduction of downtime due to system reconfiguration, failures, and maintenance.
One method of replacing and/or adding individual devices in a network, without taking action to remove electrical power from a system, is known as xe2x80x9chot swap and add.xe2x80x9d In this method and system, in order to remove an individual device from the collective system, to replace an individual device with a new one, or add a new individual device to the collective system, only the particular individual device which is to be replaced or is to be inserted is powered down, while the remaining slots, elements, components, devices, and subsystems of the network remain operational. Using such a method, network operations and service to clients is minimally disrupted. In some embodiments of this hot swap method, the physical removal of an element from the collective system automatically removes power, and the maintenance and repair personnel take no separate action to remove power.
In some configurations, elements of the collective system support hot swapping by connecting a data interface through xe2x80x9cblind connectors.xe2x80x9d These blind connectors mate to a xe2x80x9cbackplanexe2x80x9d board or other similar device in a rack, a computer, switch, router, server, or other system. This type of connection is well known in electronics, and is desirable because the physical act of placing the element into its desired location is also the act that establishes the power and data connections. No separate actions are required to attach connectors, to mate cables, or to connect power.
In some configurations, elements of the collective system are mounted in an equipment rack. As the size of network elements and other network system elements have been reduced, the number of interconnections on the front and back of such racks have become problematic. When a very large number of wires must be connected in a small space, several problems may be experienced. Among these problems, are that the tangle of the connectors leads to errors in connection and disconnection, and, that connections, which must not be turned more tightly than a prescribed radius, are often degraded.
While many of the above-described techniques and devices have been discussed in the context of electrical communications systems, there is currently a need for such techniques and devices in optical communications systems.
A number of embodiments of optical transmitters and receivers capable of data transmission and reception at rates well above one hundred million bits per second, and even above one billion bits per second, are currently used. The cost of some of these devices has become quite low, in part due to their popular use in consumer entertainment devices, and in computer data storage devices. In addition, even higher performance transmitters and receivers are well known and understood in the fields of optical networking. These telecommunications class devices are used in a variety of optical communications systems and applications.
A growing field of interest is the use of optical interconnections to provide data bandwidths higher than is practical with connections made by conductive wires and electronic signals. Examples of such interconnections include the GigE version of Ethernet communications, which may operate at a fundamental bit rate of one billion bits per second. Higher speed networks, which are expected to be implemented only by means of optical interconnects, are also becoming prevalent.
Existing optical interconnections do not lend themselves well to the electronic hot swap methodologies, because they require alignment of the optical fiber at each connection to devices such as, but not limited to, optical transmitters, optical receivers, optical splitters, fiberoptic splices, DWDM management devices, and at any other optical fiber interconnection point, whether for a single mode or multi-mode fiber. The requirement to insure proper connection and termination of optical fibers requires special tools, operator training, and repair time, among other limitations which are well known in the art of fiber connections.
A number of approaches have been proposed to reduce the costs of optical fiber interconnections, to improve the quality of the resulting interconnections, or to achieve both ends. For example, see U.S. Pat. No. 6,253,011 to John M. Haake and entitled xe2x80x9cMicro-aligner for precisely aligning an optical fiber and an associated fabrication method.xe2x80x9d In addition there are a number of available connectors and patch cords, which incorporate some of the characteristics of electrical connectors. However, optical connections, even when made with these aides, are still very vulnerable to contamination by debris in the optical interface, may involve considerable signal loss, and may require use of optical coupling gel to assure consistent performance.
A number of approaches have been proposed to provide for the connection of a plurality of optical signals. Most of these involve opto-electronic devices, micro-electro-mechanical system (MEMS) shutters or matrices of active mirrors, the use of optical waveguides, or some combination of these elements (for example, see U.S. Pat. Nos. 4,910,396, 6,212,314, and 6,234,688). None of these approaches, however, eliminate the need for fiber optic connections.
Thus, even in the context of devices designed for hot swapping, much of the prior art systems, methods, and processes are tedious, are not conducive to preventing mistakes, and can lead to additional network performance problems, outages, and service delays. In the context of systems that need an arbitrary number of connections, the dependence on splitters or switches is not conducive to several desirable optical network topologies.
Accordingly, what is needed in the art is an optical communications system that may take advantage of many of the above-referenced benefits of the electronic communications systems, however, one that does not have many of the drawbacks associated with the optical communications systems currently used today.
To address the above-discussed deficiencies of the prior art, the present invention provides in part an optical backplane for use with a communications equipment chassis. The optical backplane, in one embodiment of the invention, may include a reflector system coupled to a wall of a communications equipment chassis and having a signal incidence surface and a signal reflective surface. The signal incidence surface may be positioned on the wall and optically alignable with a transmitter positioned within the communications equipment chassis. Further, the signal reflective surface may be positioned on the wall and optically alignable with a receiver positioned within the communications equipment chassis.
The present invention is further directed to an optical communications system including the optical backplane, and a method of use therefor. In addition to the elements of the optical backplane disclosed above, the optical communications system may include a communications equipment chassis having a transmitter and a receiver positioned therein, wherein the transmitter and receiver are aligned with the signal incidence surface and signal reflective surface, respectively.
The foregoing has outlined preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that fallows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.